Pituitary calcium channel modulation and regulation of prolactin gene expression.
Pituitary calcium channel modulation and regulation of prolactin gene expression.
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DOI：
10.1210/mend-4-5-736
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发表时间：
1990-05
影响因子：
--
通讯作者：
R. Day;R. Maurer
中科院分区：
文献类型：
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作者：
R. Day;R. Maurer
用二氢吡啶类钙通道调节剂BayK 8644（R5417）和尼莫地平研究了电压门控性钙通道在GH 3细胞PRL基因转录调节中的作用。在GH 3细胞中瞬时表达含有来自连接至细菌氯霉素乙酰转移酶（CAT）基因或萤火虫荧光素酶基因的大鼠PRL基因的5 '-侧翼序列的融合构建体，并评估对Ca 2+通道调节剂的转录应答。Ca ~（2+）通道激动剂R5417可增强含有2.5 kb的5 ′-侧翼序列的PRL-CAT融合基因的转录。该反应被Ca 2+通道阻断剂尼莫地平完全阻断，表明PRL 5 '侧翼区的序列赋予对Ca 2+的反应。用含有2.5kb至0.6kb的5 ′-侧翼序列对的PRL-CAT构建体转染对Ca 2+有响应，尽管含有远端增强子区（位置-1765至-1495）的那些具有高得多的基础表达。通过比较近端增强子区域和远端增强子区域对R5417和TRH的反应，测试远端增强子可能含有Ca 2（+）-响应元件的可能性。（5 ′-侧翼序列的大约前300个碱基对）和与胸苷激酶启动子和CAT连接的远端增强子区域。结果表明，这两个区域有助于对Ca 2+的总体转录应答和TRH。远侧区域不赋予对佛波酯的反应，而近侧区域对该治疗有反应。（250字处删节）
The dihydropyridine Ca2+ channel modulators (-) Bay K 8644 (R5417) and nimodipine were used to study the role of voltage-gated Ca2+ channels in the regulation of PRL gene transcription in GH3 cells. Fusion constructs containing 5'-flanking sequences from the rat PRL gene linked to either the bacterial chloramphenicol acetyltransferase (CAT) gene or the firefly luciferase gene were transiently expressed in GH3 cells and the transcriptional response to Ca2+ channel modulators was assessed. The Ca2+ channel agonist R5417 enhanced the transcription of a PRL-CAT fusion gene containing 2.5 kilobase (kb) pairs of the 5'-flanking sequence. This response was completely blocked by the Ca2+ channel blocker nimodipine demonstrating that sequences in the PRL 5'-flanking region confer response to Ca2+. Transfection with PRL-CAT constructs containing 2.5 kb to 0.6 kb pairs of 5'-flanking sequence were responsive to Ca2+, although those which contained the distal enhancer region (positions-1765 to -1495) had much higher basal expression. The possibility that the distal enhancer might contain Ca2(+)-responsive elements was tested by comparing the response to R5417 and TRH for both the proximal enhancer region (approximately first 300 base pair of the 5'-flanking sequence) and distal enhancer regions linked to the thymidine kinase promoter and CAT. The results demonstrate that these two regions contribute to the overall transcriptional response to Ca2+ and TRH. The distal region does not confer a response to phorbol ester, while the proximal region is responsive to that treatment.(ABSTRACT TRUNCATED AT 250 WORDS)